The Effects of Bowing Distortions on Heat Trannsfer in a Seven-Pin Bundle

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Haga, K.*; Daigo, Y.*; Kikuchi, Y.*; Otsubo, A.*

Haga, K.*; Daigo, Y.*; Kikuchi, Y.*; Otsubo, A.*

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This paper deals with the experimental results of heat transfer in sodium flowing in an electrically heated seven-pin bundle where a pin was bowed to form a point contact. Each pin was 6.5 mm in diameter and had a 450 mm heated length. The bundle was tightly packed with 1.3 mm diameter spacer wires and placed in a hexagonal tube. The pitch-to-diameter ratio (P/D) was 1.22. The central pin was bowed symmetrically near the axial mid-plane to form a point contact with an outer normal pin. The measured temperature rise due to the point contact compared fairly well with the calculation by the PICO code. In addition, experiments were carried out with the normal pin bundle to establish a base case and to evaluate the effect of mixing due to spacer wires. When applied the experimental results to reactor conditions, the temperature rise due to a point contact is considered to be less than 30k.